Means for rolling thin sections



Sept. 11, 1928. 1,684,206

J. w. SMITH MEANS FOR ROLLING THIN SECTIONS Filed March 14, 1927 2Sheets-Sheet 1 g l II:III; R

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FIG- I.

Sept. 11, 1928.

J. W. SMITH MEANS FOR ROLLING THIN SECTIONS Filed March 14, 1927 2Sheets-Sheet IIIIIIIIIE INVENTOR:

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BY W

ATTORNEYS.

Patented Sept. 11, 1928.

UNITED STATES 1,684,206 PATENT OFFICE.

JOHN W. SMITH, OF PHILADELPHIA, PENNSYLVANIA.

MEANS FOR ROLLING THIN SECTIONS.

Application filed March 14, 1927. Serial No. 175,335.

tember, 1926; I have set forth a two-stage process of fabricating thinsections involving a high-speed rolling mill for the second stage. Undersuch process I am enabled to roll die forged blanks to thin sections byutilizing the heat retained in the blankafter a first stage forging.Cycloidal rolling, by multiple passes, has been found highlyadvantageous in producing comparatively thin sections from relativelythick material when carried out at high speeds inasmuch as, suchsections expand more readily when cycloidally rolled than when rolledwith" a straight'line motion.

Cyclodial rolling and multiple drive eliminates the buckling or plaitingof the metal when rolling near the outer edge and facilitates reducing acomparatively thick material to the required thin section in one pass,making use of the second pass as a finish, or eliminating it entirely oncertain classes of work.

Arcograph rolling is often an advantage in producing the final shape. Myintegral hub and brake drum is a. typical example to illustrate mymultiple drive arcograph rolling and forms a part of my process formaking integral hubs and brake drums and similar articles.

Maximum reduction in reducing metal by the rolling process is to be hawhen power is applied to all of the rolling means 3).) this particularcase, one revolving forming die is employed, and two reducmg rollers,each of the three means being supplied with power.

Having briefly outlined the mechanical organization involved I will nowset forth the novel features more particularly. Primarily, it is well tohere remark, that during the rolling period I aim to maintalnco-operative synchronized torque between the motors driving the rollingand forming means. Such synchronized or balanced torque might beattained by mechanical means, but I prefer to control the momentum ofthe forming die so that it attains the proper 0 synchronized speed whenthe milling rollers are initially moved into rolling location, inasmuchas a surface speed change of four-- to-one between the outer and innerperipl cry may be necessary in some cases. In other 5 words, I aim tomaintain a co-operative speed and torque for the forming die with abalanced torque as between the motors driving the rolling means, byautomatically synchronizing the surface speeds of the 7 forming die withthe milling rollers.

The primary object of the instant'invention, accordingly, is to rollthin sectionswith a combined radialor cycloidal'and synchronized surfacespeed as between the forming and rolling means at all the varyingcooperative positions assumed incidental to the rolling operation.

Another object is to efiiciently fabricate such sections with greaterrapidity than is at present ossible by known means.

Other ob ects and advantages will be apparentfrom the followingdescription of a typical means effective to carry out this invention;while the appended claims serve to define those features alleged asnovel and patentable.

In the drawings Fig. I is a sectional view of the upper portion of arolling mill adapted to my present improvements.

Fig. II is'an axial section through a preformed or forged blank readyfor rolling in accordance with this invention.

Fig. III is a similar view illustrative of the section after radialrolling in accordance with one phase of the present invention; and,

Fig. IV is a corresponding section of a typical product of the presentinvention subsequent to a final stamping and machining operation.

Before entering upon a detailed explanation of the mechanism typified assuitable for carrying out my presentwimprovements in the art of rollingthin sections, I would here remark that this invention is mainly-- Inview of the fact that the mill illustrated chronized multiple-driveinstrumentalities.

in Fig. I generally conforms to that described in my co-pendingapplication Serial Number 713,425, supra: the following deplace by acap-piece 9 seating over an annular ledge of the housing 6, and a thrustbearing 10 thereunder, so as to ensure perfect freedom of rotation. As ameans for driving the revolving die head 8 I-preferably-make use of aco-operatetorque variablespeed motor 11,. designed to furnish therequired torque or moment of force required by the revolving die 5."

This motor 11 is supported upon the top of the mill 6 by means of asuitable mounting 13 secured to the ring 12, while the shaft 14 of saidmotor is coupled direct to the revolving die head cap-piece 9 by acoupling 15.

A suitable blank 16such as shown in Fig. II for exampleis sustained inthe mill resting against the extraction pin 17 and securely held inplace by a stud 18 mounted on the turret-head 19, which has capacity forrotary-and vertically slidable-movement; all as described in thehereinbefore referred to co-pending application.

The rollers 20 functional to radially expand the blank 16 relative tothe forming and rolling die 5 are provided with shafts 21 journaled inball and roller bearings 22, 23respectivelyin turn appropriately securedin trunnion housin s; 24, 25 sustained by a trunnion support mounted onthe mill main columns 26. Each housing 24, 25 is fitted with a cap piece27 serving to support the electric motors 28, 29, respectively; whichare directly connected to the aforesaid shafts 21 through the medium ofcon lings 30.

aving briefly outlined the mechanical organization involved I willnowset forth the novel features more particularly. Primaril it is wellto here remark, that during t e rolling period I aim to maintainco-operative synchronized torque between the motor 11 and motors 28, 29.Such synchronized or balanced torque might be attained b mechanicalmeans, but I prefer to contro the momentum of the forming die 5 so thatit attains the proper synchronized speed when the millin rollers 20, 20are initially moved into r'o ling location adja cent the blank boss 31,inasmuch as a surface change of four-to-one between the periphery andsaid boss may be necessary in some cases. In other words, I aim tomaintain a co-operative torque for the die 5 with a co-operativebalanced torque as between the motors 28, 29 by automaticallysynchronizing the surface speeds of the die 5 with that of the rollers20.

In conjunction with the means just explained I employ a rheostat 34 forautomatically regulating the strength of a shunt field 35 of the motor11, with a co-ordinating connection 36, pivoted at 37 to one25 forexample-of the trunnion housings, and sim ilarly connected at 38 to theswitch arm 39 of said rheostat. Thus it will be readily appreciatedthat, as themilling rollers 20,

20 swing radially relative to the forming die 5, the resistance in theshunt field circuit 35 r of the motor is automatically controlled.

The requirements for driving rollers 20, 20 are constant revolutions perminute and constant torque. V

The requirements for driving the die ,5 are entirely dilierent. Near thecenter the revolutions per minute are high with a correspondingly lighttorque, and on the outer edge the revolutions per minute are low with aheavy torque. The above requirements are in accord with shunt woundmotor s ccifications requiring a light torque wit a gvqalk field, and aheavy torque with a strong Rolling at constant periphery speed as setforth is an important factor 1n my process. Applying the automaticrheostat to motor 11, the re uirements are more easily met than if appied to motors 28 and 29..

The three motor or multiple drive herein shown represents a drive of thesimplest form. The die head 8 is driven by a variable speed shunt woundmotor with an automatically operated rheostat 34. The milling rollers 20are driven by motors 28 and 29 which are com ound wound motors with asuitable preme itated speed factor between no load and full load.

In this particular case the series field cir-.

cuits 32 of. motors 28 and 29 are connected in parallel. Some motormanufacturers would prefer to connect the series fields in seriesformotors 28 and 29. The shunt field for motors 28 and 29 are hereinshown in parallel' but they may also be connected in series. Motor 11may also be supplied with a series field winding connected in serieswith motors 28 and 29 as a means of augmenting co-operative performance.

The power lines for the motors 11 and 28, 29 are, respectively,designated by the .numerals 40, 41, although it will be readilyunderstood that all of said motors may be served from one such line;whilegisuch indicationsin this, ;case--are solely' by way ofillustrating diagrammatically one convenient arrangement.

Referring onceagain to I it W111 be loo remarked that I have shown theface of the die 5 is of a curvature not struck from a common center butrather of gradual deviation outwardly therefrom, with the result thatthe milling rollers 20, 20 roll the blank 16 cycloidally to taperingcross section. On the other hand m present invention is par; ticularlywell a apted for the rolling of thin sections having the dished contourdepicted at 42 in Fig. III, that is to say with a definite radialcurvature and of even seetional gage. Such profiled sections areparticularly well adapted for subsequent die stamping to the sectionalformshown at 43 in Fig. IV-and useful as integral hub and brake drumunits for thin section spokeless wheels.

From the foregoing it is thought my present invention will be wellunderstood, and while I have outlined one typical embodiment thereof, itis to be understood that I hereby reserve the right to vary the meansadaptable for ensuring the generic aspects of said invention so far asis compatible with reasonable interpretation accorded the subjoinedclaims.

Having thus described my invention, I claim:

1. In a rolling mill embodying a rotary forming die and co-operativcrolling means movable radially of the forming die, the combination ofmeans with automatic control to positively drive the forming die and therolling means at synchronized surface speed in different co-operativepositions assumed incidental to the rolling operation.

2. In a rolling mill embodyin a rotary forming die and co-operative roling means movable radially of the forming die, the combination of meansto positively drive the rolling means at synchronous speed, separatemeans to drive the rotary forming die, and automatic means to controlthe drive means aforesaid for maintenance of synchronized surface speedsbetween the rota forming die and the rolling means in di erentco-operative positions incidental to the rolling operation.

3. In a rolling mill embodyin a rotary forming die and co-operativerolfing means movable radially of the forming die, the combination ofmeans to positively drive the rolling means at synchronous speed,separate means to drive the rotary forming die, and automatic meanscontrolling coordination of the respective drive means for maintenanceof co-operative balanced torque between the several drive means.

4. In a rolling mill embodying a rotary forming die and co-operativerolling means movable radially of the forming die, the combination ofmeans to positively drive the rolling means at synchronous speed, separate means to drive the rotary forming die, and a control functional toco-operatively balance the torque between the respective drive means.

5. In a rolling mill embodying a rotary forming die and co-operativerolling means movable radially of the forming die, the combination of anelectric motor to positively drive the rolling means at synchronousspeed, a separate electric motor to drive the rotary forming die, arheostat in circuit with said latter motor, and means adapted toautomatically vary the strength of a shunt fieldthrou h saidrheostatsynchronously controlled by the varying location of the rollingmeans.

6. In a rolling mill embodying a rotary forming die and co-operativemultiple-rolling means movable radially of the forming die, thecombination of an electric motor with means to varyingly balance thespeed of each rolling unit, a separate electric motor to drive therotary forming die, and a rheostat--operatively co-ordinated with one ofthe rolling units-functional to vary the electro-motive force through ashunt field of the forming die motor, whereby the torque of the latteris co-operatively balanced relative to that of the rolling unit motorsincidental to the peripheral speeds of said rolling units.

7. In a rolling mill embodyin a rotary forming die and co-operative muti le-rolling means movable radially of the orming die, the combinationof an electric motor with a series and shunt fields adapted to eachrolling unit, a separate similar motor to drive the rotary forming die,.and a rheostat co-ordinated with one of the rolling units functional tovary the strength of the shunt field of the rotary forming die motorwhereby the torque of the several motors is co-operatively balanced.

8. In a rolling mill embodying a rotary forming die and co-operativemultiple-rolling means movable radially of the forming die, thecombination of an electric motor for each operative unit with a parallelcircuit for series and shunt fields, means functional to co-operativelybalance the torque between the respective motors, and the aforesaidseries field and shunt field circuits being connected in parallel.

In testimony whereof, I have hereunto signed my name at Philadelphia,Pennsylvania, this 10th day of March, 1927.

JOHN W. SMITH.

